Imagewise priming of non-D2T2 printable substrates for direct D2T2 printing

ABSTRACT

A method for enabling D2T2 printing onto non-D2T2 printable substrates uses a diffusible primer material provided on a dye-sheet or ribbon. The primer comprises a polymer, a release agent and a plasticizer. The release agent and the plasticizer are diffused into the substrate, while the polymer remains on the dye-sheet or ribbon. Printing of the primer onto the PC substrate is controlled via a computer image program corresponding to a colored image. This computer image program also controls the printing of the colored image at the primed locations. Accordingly, image-wise treatment of a plastic material via the primer selectively renders the PC substrate surface D2T2 printable at the point of personalization, providing for a 100% PC full card body having the colored image.

TECHNICAL FIELD

The exemplary teachings herein pertain to methods and techniques forenabling D2T2 printing onto non-D2T2 printable substrates, and inparticular, to the image-wise treatment of a plastic material toselectively render the surface D2T2 printable at the point ofpersonalization. Specifically, the present disclosure relates to one ormore processes for the image-wise plasticization or priming ofpolycarbonate or other non-D2T2 printable substrates for direct D2T2printing, to one or more D2T2 ribbons used to accomplish the same, andto the products made by the one or more processes.

BACKGROUND

Dye diffusion thermal transfer printing (D2T2, also known asdye-sublimation or dye-sub), is a common digital printing technique inthe ID card and security industry. To print a digital image using D2T2,a dye-sheet containing the dyes and a substrate known as a receiver isrequired. All receiver substrates must be able to accept the dyes duringprinting and to separate from the dyesheet without sticking. This can bea simple polymer that is able to accept dyes or a specially designedreceiver coating that has been designed to function in a dye diffusionprinter, as is the case in digital photography.

PVC is a widely used substrate in the card D2T2 printing industry due toits combination of properties: low cost; good dye receptivity; and itdoes not stick during printing. However, it has a relatively poordurability and is not the preferred substrate for other securityprinting techniques such as laser engraving. There are a number of othersubstrates of interest within the printing industry that offer certainadvantages over PVC but there are various limitations to thesealternative substrates.

In particular, polycarbonate (PC) is becoming a substrate of interestfor card and ID applications, such as driver's licenses, student IDs orother ID cards, security badges, credit and debit cards and the like,due to its ability to be laser engraved and its general durability.However, PC cannot be directly printed by the common printing techniqueof dye diffusion thermal transfer (D2T2) printing. This is because thedye-sheet sticks to the PC surface during the high temperature, intimatecontact of the D2T2 printing process, and the material also has poor dyereceptivity for the dyes commonly used in D2T2 printing. The ability todiffuse small molecules from a polymer matrix is well known in the artas it forms the basic concept of D2T2 printing (see, e.g., Europeanpatent number EP0399690, the entire disclosure of which is hereinincorporated by reference).

Accordingly, in D2T2 printing, a dye-sheet or ribbon is positioned inintimate contact with a substrate, on which it is desired to print acolored image. The dye-sheet or ribbon comprises a polyester (e.g. PET)substrate having a back coat, and a plurality of panels affixed in asuitable manner known in the art to the PET substrate on the sideopposite the back coat. To aid adhesion of dye panels, an adhesive layercan be used on the PET base. This adhesive layer can be applied duringbase manufacture or coated onto PET prior to coating dye formulations.

Any mass transfer panel contained within a dye-sheet can be formulatedsuch that it releases directly from PET base, or they can be applied ontop of a releasing sub-coat. In the case of a base having a continuousadhesive applied prior to coating the panels, the releasing sub-coat maystill be used.

A standard commercially available YMCKO dye-sheet or ribbon isillustrated in FIG. 1. As can be seen in FIG. 1, the five panels areaffixed to the PET substrate, the last two removably affixed via a subcoat. These five panels in order are a yellow dye panel (Y), a magentadye panel (M), a cyan dye panel (C), a black mass-transfer panel (K) anda mass transfer panel which can be used as a protective overlay (O),hence the acronym YMCKO. Ribbons may be of any format and panel lengthand other options are available, these include but are not limited tosingle color ribbons, YMC, YMCK, and YMCKOK. Other optional panelsinclude but are not limited to diffusible security features, e.g.,diffusive UV dyes, or other mass transfer features, such as UV pigments,metallic pigments, Optically Variable Pigments, taggants, etc. DuringD2T2 printing, the dye-sheet or ribbon is indexed over the substratesuch that each of the panels is positioned over the substrate insuccession. As is known in the art, a computer controlled thermal printhead selectively heats each of the panels in the desired locationsdetermined by a computer program to produce a colored image on thesubstrate.

The back coat on the PET substrate of the dye-sheet or ribbon aids inthe transport across a thermal print head, and transfers heat from thethermal print head through to the dye-coats. When the yellow, magentaand cyan panels are heated, in turn, the respective colored dye isdiffused from the panels at the locations where the heat is applied toproduce the respective color on the substrate to form the imageaccording to the computer image program. The amount of dye transferredis dependent on the temperature of the pixel of the print head. This isdifferent from a mass transfer printing process where the transfer iseither “on” or “off,” and an image is built up with a dithered patternof colored dots. In the D2T2 process, 256 shades of each component colorcan be achieved and each component color can be blended with the othertwo component colors, giving a huge color gamut (16.7 million colors),and hence, continuous tone images are possible. The panels comprise apolymer and the dye, which when heated causes the dye to diffuse ontothe substrate, while the polymer remains attached to the PET substrateof the dye-sheet or ribbon.

The black panel is attached to the PET substrate, for example via asub-coat, which allows the black panel, comprising a polymer and a blackpigment, to be transferred to the card substrate at the locations whereheat is applied. Thus, unlike the yellow, magenta and cyan panels, boththe polymer and the black pigment of the black panel are transferred tothe substrate where heated. Similarly, the mass transferable protectiveoverlay panel (O) is completely transferred from the dye-sheet or ribbonand onto the substrate where heated, typically over the entiresubstrate. Other panels are possible and may be included, which canfunction as either diffusion or mass transfer depending on the materialsused. These panels can function as security features when usingmaterials that are fluorescent under UV light, optically variablepigments, taggents, etc.

As is known, a PC substrate is a non-D2T2 printable substrate. Whenconventional D2T2 printing is tried on PC, only extremely low densityimages can be achieved, which have unacceptable low density. Morecommonly, the dye-sheet will stick during the printing operation,However, there are a number of alternative ways in which color imagescan be added to PC. For example, a color image could be added to PC byusing a mass transfer printing technique, wherein a thermal transferribbon (TTR) is used to transfer the polymer and pigment onto the card(as opposed to D2T2 or dye-sublimation). Such a method has thelimitation that the image will not be of the same quality as a D2T2image due to the necessary dithering of the image, resulting in lowerquality printing.

A color image could also be added to PC by pre-coating the PC with animage receiving layer such as a copolymer of polyvinyl chloride/vinylacetate. A product of this type is commercially available from BayerMaterials known as Makrofol ID. This option has the limitation that aspecific pre-coated card stock is required, which may be more expensive,and the entire upper surface of the card is no longer PC.

Another method of adding a color image to PC is by thermallytransferring a receiver layer as a mass transfer patch, of any shape orsize, from a ribbon onto a particular area of the substrate. FIG. 2illustrates a D2T2 dye-sheet or ribbon used in this method. The generalconcept of a thermally transferable receiver layer is disclosed by anumber of patents including U.S. Pat. No. 5,006,502 and EP0333873,JP62297184, and JP61084281. The disclosures of each of these patents areherein incorporated by reference. As shown in FIG. 2, a thermallytransferable dye receptive layer or patch is removably attached to aD2T2 dye-sheet or ribbon, which can be via a sub-coat, in front of theyellow dye panel. As such, the first layer or patch, when heated, istransferred to the PC card substrate prior to D2T2 printing.

Subsequently, a colored image can be D2T2 printed onto this thermallytransferable dye receptive layer or patch. This option leaves most ofthe card surface as PC, which has an advantage over the option ofpre-coating the PC with an image receiving layer. However, a layer orpatch of an alternative polymer is transferred to the PC card surface sothere will still be a section of the PC substrate surface that is nolonger 100% PC.

A fourth method of adding a color image to PC is by pre-treating PCsheets to enable them to be D2T2 printed. The concept of pre-treatingthe PC sheet surface is disclosed in U.S. Pat. No. 6,867,167 issued toTrueb. However, this is a treatment of the whole card surface. Thisoption could allow a 100% PC substrate to be D2T2 printed, but thetreatment step is unrelated to the personalization step and the image.As such, this option offers no added security, and the non-imaged areasof the card could be imaged at a later stage. This would potentiallyallow tampering of an ID document.

Therefore, a need exists for an improved method of adding a color imageto a PC substrate via direct D2T2 printing, which is directed towardovercoming these and other disadvantages of prior art methods.Accordingly, to address the above stated issues, an improved method torender a PC substrate surface D2T2 printable at the point ofpersonalization is needed. The exemplary teachings herein fulfill such aneed. It is desired that the methods and techniques for providing theabove benefits be applicable to any instances or applications whereinimages are to be printed on a non-D2T2 printable surface.

SUMMARY

The exemplary technique(s), system(s) and method(s) presented hereinenable D2T2 printing on non-D2T2 printable substrates, through the useof a diffusible primer that can be printed image-wise according to acolor image to be subsequently printed. The diffusible primer comprisesa coating of polymer, plus small molecule agents that can be diffusedinto a substrate to alter its surface properties. The polymer should besuch that it adheres to the PET material and the small molecules arepreferably a release agent and plasticizer.

Release agents are commonly used in the art of D2T2 printing and includegroups such as silicone, silicone resins, modified silicones, waxes,phosphoric acid ester surfactants, fluorine surfactants, fluorinecompounds, long chain alkyl type compounds, higher fatty acid esters,and higher alcohols. However, these are typically added to receivercoatings during manufacture to assist with the release of the dye-sheetduring printing, such as described in EP 0292 109 B1, the entiredisclosure of which is herein incorporated by reference.

Plasticizers are small molecules which can penetrate a polymer matrixand reduce intermolecular forces and increase free volume by pushing thepolymer chains apart. This can make it easier for other penetrants toenter the polymer matrix. These small molecules may be solid, liquid orgas at room temperature.

The diffusible primer is coated onto a PET substrate (optionally withadhesive) with a back coat on the opposite side of the PET film. Thiscan be in a continuous format or in a paneled ribbon which can includebut is not limited to Y, M, C, K and O panels to form a dye-sheet. Otherpanels are possible and may be included which can function as eitherdiffusion or mass transfer depending on the materials used. These panelscan function as security features when using materials that arefluorescent under UV light, optically variable pigments, metallicpigments, taggents, etc.

The primer formulation is designed such that the polymer sticks to thePET base. The polymer does not transfer during printing, as opposed to amass transfer technique, and the release agent and/or plasticizer aredesigned to diffuse out of the polymer binder into the receiversubstrate, e.g., a PC substrate, at the locations at which heat isapplied.

An image may be D2T2 printed onto a PC substrate or other non-D2T2printable substrate, using this “primer” ribbon, whereby the releaseagent and/or plasticizer will diffuse from the coated polymer into thenon-D2T2 printable substrate surface according to the computer imageprogram. This renders these specific areas of the non-D2T2 printablesubstrate directly D2T2 printable. The plasticizer allows the dyemolecules from the D2T2 ribbon to enter the polymer matrix, and therelease agent prevents the dye-sheet from sticking to the receiversubstrate during the printing step.

The disclosed methods and techniques provide for the ability to transferrequired release agents and/or plasticizers from a D2T2 thermal transferribbon, without transfer of polymer, thus leaving the entire substratesurface as PC. The disclosed methods and techniques also provide for theability to transfer the release agent and/or plasticizers image-wise,thus making the substrate D2T2 printable only at the point of issuanceof the card and only according to the color image to be printed.

Additional objects, advantages and novel features will be set forth inpart in the description which follows, and in part will become apparentto those skilled in the art upon examination of the following and theaccompanying drawings or may be learned by production or operation ofthe examples.

BRIEF DESCRIPTION OF THE DRAWINGS

The drawing figures depict one or more implementations in accordancewith the present teachings, by way of example only, not by way oflimitation. In the drawing figures, like reference numerals refer to thesame or similar elements.

FIG. 1 is a schematic cross-sectional illustration of a prior art,standard YMCKO dye-sheet or ribbon;

FIG. 2 is a schematic cross-sectional illustration of a prior art D2T2dye-sheet or ribbon having a mass transfer receptive layer;

FIG. 3 is a schematic cross-sectional illustration of an exemplaryembodiment of a D2T2 dye-sheet or ribbon having a diffusible prime layeraccording to the present disclosure;

FIG. 4 is a chart showing comparative test result of examples ofspecific plasticizers and/or release agents used in accordance with thepresent disclosure;

FIG. 5 is a graph showing a comparison of the Optical Density (OD) buildup that can be achieved with an embodiment of the present teachingsverses standard PVC cards; and

FIG. 6 is a schematic diagram of an exemplary embodiment of apost-personalization plate lamination method of the present disclosure.

DETAILED DESCRIPTION

The following description refers to numerous specific details which areset forth by way of examples to provide a thorough understanding of therelevant teachings. It should be apparent to those skilled in the artthat the present teachings may be practiced without such details. Inother instances, well known methods, procedures, and components havebeen described at a relatively high-level, without detail, in order toavoid unnecessarily obscuring aspects of the present teachings.

Referring now to FIG. 3, for the sake of illustration purposes only,without limitation, one embodiment of a D2T2 dye-sheet or ribbonincorporating the teachings of the present disclosure is shown. Itshould be understood that the primer of the present disclosure can beadded to any known printing ribbon, and other ribbons incorporating theprimer of the teachings herein are contemplated. For example, the ribbonmay be a continuous format for use in modular printing machines or aspart of paneled product for use in single head printers.

In the example of FIG. 3, the D2T2 dye-sheet or ribbon of the presentdisclosure may include, for example, five panels, as illustrated,attached to a PET substrate having a back coat. The five panelsillustrated are, in order, a prime layer or panel (P), yellow dye panel(Y), a magenta dye panel (M), a cyan dye panel (C), and a black polymerand pigment panel (K). It should also be understood that the panel P canbe combined in a paneled ribbon of any format with panels of any size,and can incorporate optional extra features including but not limited todiffusible security features, e.g. diffusive UV dyes, or other masstransfer features, such as UV pigments, metallic pigments, OpticallyVariable Pigments, taggents, etc.

During D2T2 printing, the dye-sheet or ribbon is indexed over thesubstrate such that each of the panels is positioned over the substratein succession. A computer controlled thermal print head selectivelyheats each of the panels, in turn, in the desired locations determinedby a computer program to produce a colored image on the substrate.

The prime layer comprises a polymer, and a release agent and/orplasticizer. At the beginning of the D2T2 printing process, the primelayer panel is selectively heated at various locations according to thecomputer image program (i.e., image-wise), whereupon, the release agentand/or plasticizer diffuse from the panel and into the substrate,according to the computer image program, at the locations where thecolored image will be printed. When the yellow, magenta and cyan panelsare heated, in turn, the respective colored dye is diffused from theirpanels at the locations where the heat s applied to produce therespective color on the substrate, where primed, to form the imageaccording to the computer image program.

If desired, the polymer and the black pigment of the black panel canalso be transferred to the substrate where heated, to personalize thesubstrate with the desired information, which may include for example,barcodes and text. If present, a mass transfer protective overlay panel(O) could then be completely transferred from the dye-sheet or ribbonand onto the substrate where heated, typically over the entiresubstrate.

In this manner, the surface of the non-D2T2 printable substrate isrendered D2T2 printable but only in the specific location where thecolor image will be printed (i.e., image-wise), and at the point ofpersonalization. The amount of plasticizer and/or release agenttransferred at the beginning of the D2T2 printing will depend on thecolor image to be printed. If an area of high density color is to besubsequently printed, then a large amount of release agent and/orplasticizer will be transferred. If only low density color is requiredin a particular area then only a small amount of plasticizer and/orrelease agent will be transferred. This means that the non-D2T2printable substrate is rendered (at point of personalization) printableonly by that given image, as determined by the computer image program.The intensity and duration of the heat applied to the panels by theindividual heating wires of the thermal print head controls the amountof primer diffused into the non-D2T2 printable substrate in any givenlocation.

If one image was used to “prime” the card and a different image used tocolor print the card, then the high and low density areas may not alignand poor density or ribbon sticking issues would be encountered.Therefore, it is preferable to use only one computer image program tocontrol both the primer printing and the color printing. The substrateand each panel of the D2T2 dye-sheet or ribbon are specificallyregistered such that the primer printing and the color printing areproperly aligned.

As the primer is transferred according to the color image to be printed,the rest of the card surface is left unadulterated, i.e., is pure PC andhence not printable by D2T2 printing. Also as there is no mass transferof polymer during the diffusion printing step, the prime and colorprinting processes occur as a diffusion process. The card could still beclassified as “100% PC polymer” and thus still offer all of the benefitsof PC substrates.

The primer has been illustrated in FIG. 3 as a panel, forming part of apaneled D2T2 ribbon, with an acronym of PYMCK, for use in single headtype printers, where P=the primer panel. It should be understood howeverthat the primer could be coated as a continuous coating on to a basematerial to create a continuous primer ribbon for use in a central issuemodular type D2T2 printer. It should also be understood that the panel Pcan be combined in a paneled ribbon of any format with panels of anysize. Some of the benefits the presently disclosed method and systemhave over the prior art are the ability to transfer required releaseagents and plasticizers from a thermal transfer ribbon, without transferof the polymer binder (leaving the entire surface as PC), and theability to transfer the release agent and plasticizers image-wise, thusmaking the substrate D2T2 printable only at the point of issuance of thecard and only according to the color image to be printed.

A further embodiment of the present disclosure would be to utilize theabove image-wise “priming” of a non-D2T2 printable substrate such as PC,and combine this with an in-line plate lamination technique as describedbelow. Combining these two techniques would allow production of a 100%PC substrate with a D2T2 image within the card body, thus making itextremely durable and tamper proof.

Currently, color personalization occurs after a full card body has beenformed, and the image is formed on the card, not in it. In this case,the image can be protected post-printing with an overlay or a laminate,but this can have lifetime and/or tamper proof limitations.

Imaging of cards prior to full formation and cutting into standard CR80card size can be done currently but only on a large scale. That istherefore not individual card personalization but merely backgroundimaging. If full card body formation could be done post-personalization,then an individually color imaged card with excellent durability wouldbe produced. In order to solve this problem, an in-line card-sized platelaminator is disclosed in FIG. 6. The initial card stock to be usedwould not be of full card size thickness. This initial card stock wouldbe printed with D2T2, TTR or any other such imaging technique. Theinitial card stock would then be passed into a miniature plate laminatoralong with a thin sheet of plastic of the same type as the printedinitial card stock.

Application of heat and pressure would allow the two plastic sheets tofuse, and a full card body of standard thickness with a full colorpersonalized image within the card body would be formed. This techniquecould be combined with the above disclosed image-wise plasticization ofPC to allow a full color D2T2 image to be formed within the body of a100% polycarbonate card.

The technique of forming the full card body structurepost-personalization need not be limited to an in-line process. The sametechnique of taking a non-full thickness pre-personalized plasticmaterial and forming the full card body structure post-personalizationcould be used in an off-line plate laminator, more preferably a larger,stacked plate laminator such that a number of cards could be produced atonce, and therefore keeping pace with the personalization step.

A combination of these two techniques could allow formation of a 100%PC, full card body with an encapsulated D2T2 image. However, evenwithout post-personalization plate lamination, this resulting 100% PC,full body card with D2T2 image still offers further benefits for secureID documents over the prior art. If a counterfeiter attempts to removethe D2T2 image, he/she would also remove the ability to D2T2 print thesubstrate, therefore making it extremely difficult for the counterfeiterto add an alternative image. “Solvent washing” the image from the PCsubstrate would also wash away the release agent and plasticizer thathad been previously applied, thus rendering the PC surfacenon-D2T2-printable again. If a “shaving” technique of removing the toplayer of the PC surface were utilized, the release agent and plasticizerwould again be removed along with the color image, and the PC substratewould be rendered non-D2T2-printable.

Even if no “removal technique” is utilized and the counterfeiterattempts to alter the image in a more subtle manner, e.g., adding a darkbeard to a pre-existing ID image, then this technique should stillprevent easy tampering. As the prime is applied image-wise via adiffusion technique, even if an area has been rendered “printable,” itis not an “on/off” printable situation. If the original image were oflow density, then prior to printing the legitimate image, only a lowlevel of prime will have been transferred. Therefore, if a darker imageis printed on top of the original image, the above mentioneddifficulties of D2T2 printing PC will still exist.

EXEMPLIFICATION

By way of example, “Primer” ribbons as illustrated in FIG. 3 wereprepared by making a solution of polymers designed to adhere to a PETbase whilst allowing small molecules to diffuse from the polymer matrixwhen heated. To aid adhesion of the formulations as per the invention,an adhesive layer can be used on the PET base. This can be eitherapplied during the PET manufacture or coated onto the PET prior tocoating the formulations of the invention. The basic polymer formulationwas based on previously patented formulations as per EP0399690, theentire disclosure of which is herein incorporated by reference. However,the scope of this disclosure is not limited to the polymeric bindersystem listed here, and is given only as an example. Alternative binderpolymers may be utilized depending on the specific requirements of thechosen plasticizer and release agent. To the basic polymer formulation,a range of release agents and plasticizers were added as describedbelow. These are given as an example only and do not indicate a completelist of possible materials, and are not limiting,

Sample Preparation—Stock solutions of the binders were prepared asfollows:

Polyvinyl Butyral (PVB) Stock

-   20 g PVB BX1-   160 g THF    Ethyl Cellulose (ECT) Stock-   ECT T10-   40 g THF

These were used to prepare solutions as follows:

Solution A

Plasticizer Only (Comparative)

-   0.4 g Plasticizer-   4.3 g PVB stock-   0.6 g ECT 10 stock-   7.0 g THF    Solution B    Plasticizer+Release Agent (Invention)-   42 g PVB stock-   6 g ECT 10 stock-   2 g Solution A-   70 g THF

0.2 g of the release agent was then added to 9.8 g of the above stockand stirred for at least half an hour prior to coating.

Coatings were applied using an MB3 meyer bar to a 6 micron Diafoil K206base that had been previously coated with a back coat (used to protectthe PET base during printing) as per previous disclosures EP0703865 andEP0547893, the entire disclosures of which are herein incorporated byreference. The coatings were spliced into a standard D2T2 ribbon andprinted as a dye diffusion panel onto polycarbonate substrates using adesktop D2T2 printer (Evolis, Pebble-3). Other printers may be used andthe choice of printer was only used as an example. The teachings hereinare applicable to all D2T2 printers. D2T2 color images were then printedusing a standard YMCKO ribbon (ITW Imagedata).

Examples—Comparative vs. Invention

The following compounds were tested as plasticizers:

-   “Dinch”=Hexamoll DINCH-   “DMI”=Dimethyl Isophalate-   “ADP”=Adipic acid-   “OCT”=1,8 octanediol-   “Phs”=Phenyl Salicylate

The following compounds were tested as release agents:

-   “Tego 410”=Tegoglide 410-   Diax 2770-   “Tego 450”=Tegoglide 450-   Crodafos T5A

The result of this comparative testing is illustrated in FIG. 4.

The graph of FIG. 5 shows a comparison of the optical density (OD) buildup that can be achieved with the primer of example 8, against standardPVC cards. Clearly when utilizing this primer, PC substrates can berendered D2T2 printable, and optical densities equivalent to printing onstandard PVC cards can be achieved.

The amounts of release agent and plasticizer used in the aboveexperiments are not fixed and are given as an example only. Theconcentrations of release agent and plasticizer may be varied dependingon the level of release and improvements to dye receptivity required.The concentrations could also depend on choice of non-D2T2 substrate tobe printed, dyesheet properties and printer requirements.

While the foregoing discussion presents the teachings in an exemplaryfashion with respect to the disclosed methods and techniques forenabling D2T2 printing on non-D2T2 printable surfaces, and the productsproduced by the methods and techniques, it will be apparent to thoseskilled in the art that the teachings may apply to any type of printingor application that requires the treatment of the surface of asubstrate. Further, while the foregoing has described what areconsidered to be the best mode and/or other examples, it is understoodthat various modifications may be made therein and that the subjectmatter disclosed herein may be implemented in various forms andexamples, and that the teachings may be applied in numerousapplications, only some of which have been described herein.

What is claimed is:
 1. A diffusible primer material, releasablycontained within a non-transferrable polymer binder on a carriersubstrate, that can be printed image-wise to make plastic substratesD2T2 printable, wherein the diffusible primer material comprises arelease agent and a plasticizer.
 2. The diffusible primer material ofclaim 1, wherein the carrier substrate is a polyester film.
 3. Thediffusible primer material of claim 1, wherein the carrier substrate isa dye-sheet.
 4. A D2T2 thermal transfer ribbon comprising: a diffusibleprimer material in the form of a panel, wherein the diffusible primermaterial comprises a release agent and a plasticizer, and is releasablycontained within a non-transferrable polymer binder on a carriersubstrate, and at least one color panel on the carrier substrate;wherein the release agent and the plasticizer are adapted to diffuseinto a polycarbonate substrate upon heating of the panel of diffusibleprimer material.
 5. The D2T2 thermal transfer ribbon of claim 4, whereinthe diffusible primer material is adapted to diffuse into thepolycarbonate substrate according to a computer image programcorresponding to a color image.